Low-cost modular inductive position sensor and method of manufacturing it

ABSTRACT

A position sensor includes a plurality of E-shaped ferromagnetic cores arranged to define a circular opening therethrough to receive a shaft. Each E-shaped ferromagnetic core has a plurality of teeth, wherein adjacent E-shaped ferromagnetic cores of the arranged plurality of E-shaped ferromagnetic cores have an overlapping tooth. The position sensor further includes a frame surrounding the arranged plurality of E-shaped ferromagnetic cores, with the E-shaped ferromagnetic cores coupled to the frame.

BACKGROUND

Magnetic bearing systems, such as systems having radial and axialmagnetic bearings, both active and passive, are used in rotatingmachines, including electrical machines, such as motors, generators andmotor/generators. Position sensors for magnetic bearing systemstypically include several separate inductive or eddy-current typeproximity sensors. The sensors are placed around the rotor of themagnetic bearing system to radially and axially detect the rotorposition by measuring the distance between the rotor and the sensor tip.If the rotor position is measured in five degrees of freedom, then atleast five proximity sensors are needed to measure the two radialpositions in both ends of the machine and one proximity sensor tomeasure the axial position of the rotor. However, if a bridge connection(which enables more accurate measurement) between proximity sensors isused, even more sensors are needed, which is also the case if rotortemperature enlargement is detected by axial position measurements.

The sensors are typically quite expensive and mechanical structures alsoneed to be designed to mount the sensors. Moreover, while completepackages that include the sensors and mechanical constructions are alsoknown, the packages are even more expensive.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter.

Some examples are directed to a position sensor. Specifically, theposition sensor includes a plurality of E-shaped ferromagnetic coresarranged to define a circular opening therethrough to receive a shaft.Each E-shaped ferromagnetic core has a plurality of teeth, whereinadjacent E-shaped ferromagnetic cores of the arranged plurality ofE-shaped ferromagnetic cores have an overlapping tooth. The positionsensor further includes a frame surrounding the arranged plurality ofE-shaped ferromagnetic cores, with the E-shaped ferromagnetic corescoupled to the frame.

Other examples are directed to a rotating device. Specifically, therotating device includes a plurality of E-shaped ferromagnetic coresarranged to define a circular opening therethrough to receive a shaft.Each E-shaped ferromagnetic core has a plurality of teeth including astator tooth, wherein the plurality of E-shaped ferromagnetic cores arestacked to define offset sensing elements. The rotating device alsoincludes a plurality of wound coil bobbins having electromagnetic coilsand positioned around each stator tooth, and a frame surrounding thearranged plurality of E-shaped ferromagnetic cores, wherein the E-shapedferromagnetic cores are coupled to the frame. The rotating devicefurther includes a shaft positioned within the circular opening of theplurality of E-shaped ferromagnetic cores and a power source configuredto supply power to the electromagnetic coils. The rotating deviceadditionally includes a control circuit coupled to the electromagneticcoils, wherein the control circuit is configured to receive positionsignals from the electromagnetic coils and control the power supplied tothe electromagnetic coils to cause rotation of the shaft.

Still other examples are directed to a method for manufacturing aninductive type position sensor. Specifically, the method includesarranging a plurality of E-shaped ferromagnetic cores in an offsetstacked arrangement and defining a circular opening therethrough toreceive a shaft, wherein each E-shaped ferromagnetic core has aplurality of teeth, and adjacent E-shaped ferromagnetic cores of thearranged plurality of E-shaped ferromagnetic cores have an overlappingtooth. The method also includes coupling the plurality of E-shapedferromagnetic cores to a frame. The method further includes configuringthe E-shaped ferromagnetic cores to provide measurement signals used tocontrol rotation of the shaft when inserted within the circular openingof the plurality of E-shaped ferromagnetic cores.

Many of the attendant features will be more readily appreciated as thesame becomes better understood by reference to the following detaileddescription considered in connection with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS

The present description will be better understood from the followingdetailed description read in light of the accompanying drawings,wherein:

FIG. 1 illustrates an E-shaped core according to an embodiment;

FIG. 2 illustrates a stacked arrangement of E-shaped cores according toan embodiment;

FIG. 3 illustrates the stacked arrangement of FIG. 2 including a rotor;

FIG. 4 illustrates a stacked arrangement of E-shaped cores coupled to aframe according to an embodiment;

FIG. 5 are schematic diagrams of electrical connection arrangementsaccording to an embodiment;

FIG. 6 is a schematic diagram of an electrical connection arrangementaccording to another embodiment;

FIG. 7 illustrates a stacked arrangement of E-shaped cores coupled to aframe with a shaft inserted therethrough according to an embodiment;

FIG. 8 illustrates a stacked arrangement of E-shaped cores coupled to aframe and having a printed circuit board connection according to anembodiment; and

FIG. 9 illustrates a flow chart of a method for manufacturing a sensordevice according to an embodiment.

Corresponding reference characters indicate corresponding partsthroughout the drawings. In the figures, the systems are illustrated asschematic drawings. The drawings may not be to scale.

DETAILED DESCRIPTION

Position sensors described herein, including modular inductive positionsensors, are configured to determine sensor information for magneticbearing systems. For example, one or more positions sensors are formedfrom a plurality of E-shaped members stacked to surround and provideoffset sensing elements as part of the magnetic bearing of the system.The magnetic bearing can be any type of bearing that supports a loadusing magnetic levitation.

In particular, the position sensor in some configurations includes aframe and a plurality of ferromagnetic E-shaped cores and correspondingwindings. A position measurement circuit includes an AC voltage sourceand windings of the ferromagnetic E-shaped cores, connected to bridgeconnections, and having output voltages that are linearly dependent ofthe rotor position in x-, y-, and z-directions (i.e., zero voltage(s)correspond to the (0,0,0) position). The configuration provides alow-cost modular inductive position sensor, in part, by forming a statorcore of the sensor by placing identical ferromagnetic E-shaped corespartly on top of each other comprising a full circle. Wound coil bobbinsare mounted around each stator tooth and an assembly tool is used totune the air-gap between the stator core and rotor, which results in ahigh degree of tuning accuracy. The stator core and coil bobbins of thesensor mounted within the frame, and coils, are supplied from the ACvoltage source. The output of each coil is connected to a differentialbridge connection from which rotor positions in the x-, y- andz-directions can be measured.

In some configurations, a low-cost modular inductive x,y,z-directionposition sensor is used with a high-speed electric motor or othersimilar apparatus to detect the position of the rotor or some other typeof rotating shaft. This position sensor is suitable to be used withmagnetic bearing system in some examples because a stable positioncontrol of the rotor requires a position measurement feedback. Thepresent disclosure allows for measuring the position of the rotor of ahigh-speed electric motor with a rotation speed of several kilohertzusing non-mechanical contact configurations, particularly usinginductive measurements. However, it should be appreciated that thepresent disclosure can be applied to different non-contactless measuringprinciples, such as capacitive, eddy current, or optical measuringprinciples.

The inductive position sensor of various examples is made mechanicallyrugged and robust, able to thermally sustain high temperatures, andnon-volatile to electromagnetic interference (EMI) that can affectposition measurements.

In operation, the inductive sensor is used in, for example, a magneticbearing system to provide position feedback measurement signals for arotor position controller. That is, position feedback measurementsignals are output by the herein described configuration of sensingelements formed from ferromagnetic E-shaped cores, sensor coils woundaround suitable plastic coil bobbins and connected into a bridgeconnection, and the ferromagnetic rotor which is the measured object.The coils are supplied from a high frequency AC-voltage source (e.g.,greater than kHz range) that creates an alternating magnetic flux. Thismagnetic flux flows from the ferromagnetic E-shaped cores through anair-gap to the ferromagnetic rotor and back to ferromagnetic core viaanother air-gap. If the ferromagnetic parts (E-shaped cores and rotor)are working below a magnetic saturation flux density level, then therotor position is directly proportional to the size of air-gap betweenthe rotor and ferromagnetic E-shaped cores. That is, rotor movement inone direction increases air-gap on one side and decreases the air-gapfrom the opposite side, which changes the magnetic circuit inductanceand can be detected from the altered bridge connection output voltage.

Specifically, and with reference to FIG. 1, an E-shaped core 100 isformed by laminated electrical steel sheets or using suitable low lossferrite grades as a core material, which both reduce the amount of eddycurrents caused by the alternating magnetic flux inside theferromagnetic core. It should be noted that other ferromagneticmaterials, such solid iron/steel can be used, but high eddy currents arecaused by the high frequency of the AC voltage supply of the windingsthat results from the fast alternating magnetic flux. These eddycurrents can cause high losses and skin effects that makes the magneticflux flow only on the surfaces of the iron parts. Using a ferritematerial or laminated steel sheet structure reduces the eddy currentssignificantly and results in a lower cost of manufacture.

The E-shaped core 100 includes a middle tooth 102 between two side teeth104 extending from a base 106 that together generally define the E-shapeof the E-shaped core 100. In the illustrated example, the middle tooth102 is wider than each of the side teeth 104, which in one configurationis twice as wide, and each having the same thickness. Additionally, themiddle tooth 102 and each of the side teeth 104 have the same length inone example. However, different widths, thickness, and/or lengths arecontemplated, such as based on the particular application orconfiguration of a rotor of a magnetic bearing.

In one example, the side teeth 104 are angled inward toward the middletooth 102 such that a gap 108 therebetween decreases from a proximalposition at the base 106 to a distal position at the ends of the sideteeth 104. The amount of angle can be varied as desired or needed. Insome examples, the middle tooth 102 and side teeth 104 extend generallyperpendicularly from the base 108, which has a curved or arcuate shape.That is, the curvature of the base 108 causes the side teeth 104 to beangled relative to the middle arm 102.

The base 106 further includes slots 110 that are positioned opposite tocorresponding gaps 108. The slots 110 are thereby positioned on anopposite side of the base 106 to the gaps 108 and are together defineopenings to allow selective placement of electromagnetic coil bobbins.That is, bobbins having electromagnetic windings are positioned to allowthe flow of electrical current.

Additionally the middle tooth 102 and side teeth 104 are angled at aproximal end to form angled corners 112 within the gap 108. That is, thecorners 112 formed at (i) the proximal end of the middle tooth 102 andside teeth 104 and (ii) the base 106 are angled inward such that anon-perpendicular configuration results.

In one example, a plurality of E-shaped cores 100 are configured as asensor and that define a stator core 200 as illustrated in FIG. 2. Inthe illustrated configuration, the stator core 200 is formed from eightE-shaped cores 100 in an alternating or offset stacked arrangement. Itshould be appreciated that fewer or additional E-shaped cores 100 can beused, such as based on the size of each of the E-shaped cores 100 andthe overall size (e.g., diameter) of the stator core 200.

More particularly, each of the E-shaped cores 100 define core portions(e.g., ferromagnetic core portions of the stator core 200) and arepositioned partially overlapping or on top of an adjacent E-shaped core100 to define a circular opening 202 therethrough to receive a shaft.The E-shaped cores 100 are arranged to define a continuous circularshape of the stator core 200 wherein part of each E-shaped core 100(illustrated as an end of each of the E-shaped cores 100) overlaps withpart of the E-shaped core 100 on each adjacent side of the E-shaped core100. In this arrangement, an axial thickness (in the Z-direction) andposition of the teeth 102 and 104 of the E-shaped cores 100 (that definethe teeth of the stator core 200) vary. In the illustrated example, thethickness of overlapping teeth causes a thickness to double (i.e.,abutting teeth of the E-shaped cores 100 doubles the thickness of thethereby defined tooth of the stator core 200). In FIG. 2, the E-shapedcores 100 are arranged in a partial overlapping arrangement such thatevery second tooth is in an overlapping arrangement and in the middle(i.e., teeth 2, 4, 6, 8, 10, 12, 14, and 16 in FIG. 2), and that areused for radial direction sensing as described in more detail herein.That is, the side teeth 104 of adjacent ones of the E-shaped cores 100overlap, and the middle teeth 102 do not overlap. In one example, oneside tooth 104 of one E-shaped core 100 entirely overlaps one side tooth104 of the adjacent E-shaped core 100.

In the illustrated example, the E-shaped cores 100 are positioned tooverlap in a same axial direction, such that four of the E-shaped cores100 are positioned along a first x-y plane and the other four of theE-shaped cores 100 are poisoned along a second x-y plane parallel to andin abutting arrangement, such that the E-shaped cores 100 in each of thefirst and second parallel planes contact each other at ends thereof.Thus, as illustrated in FIG. 2, the end portions of the E-shaped cores100 a having the teeth 104 are positioned on top of the end portions ofthe E-shaped cores 100 b having corresponding teeth 104 as viewed inthis figure. Thus, in the example of FIG. 2 none of the E-shaped cores100 a are positioned below the E-shaped cores 100 b as viewed in thisfigure. As such, all of the middle teeth 102 of each of the E-shapedcores 100 a and the E-shaped cores 100 b are positioned within acorresponding x-y plane. That is, every second tooth 104 is displacedaxially from the center, such that every fourth tooth to the left sidemarked with numbers 1, 5, 9, and 13 in FIG. 2 from the center and everyfourth tooth to the right side from the center marked as teeth 3, 7, 11,and 15 in FIG. 2, and are used for axial sensing.

FIG. 2 also illustrates one example of selecting a coordinate system inwhich the +y-direction is between radial teeth 2 and 16 and +x-directionis between radial teeth 4 and 6. It should be appreciated that bymodifying the width and/or thickness of the teeth 102 and 104, themagnetic flux density flowing inside the stator teeth through the coilsis affected, thereby affecting the voltage induced to the coils and thesensitivity of the sensor.

The stator core 200 is configured to surround a measured object, forexample a rotor 300, as illustrated in FIG. 3, which defines a solidshaft. That is, the rotor 300 is positioned within the middle opening ofthe stator core 200 such that the rotor 300 and the stator core 200 areco-axially positioned. That is, the axial Z-direction is aligned withthe rotor 300 and the rotor rotation direction can be either clockwise(CW) or counter-clockwise (CCW) around the z-axis as illustrated by thearrows. It should be noted that in some examples, to facilitatecontrolling the eddy currents and the problems associated with thesecurrent, the rotor 300 includes a laminated steel sheet outer layer 302inside which magnetic flux can flow with practically zero eddy currents.

It should be noted that due to mechanical limitations, the inner part ofthe rotor 300 is formed of solid material (e.g. a suitable steel).Additionally, in FIG. 3, only part of the rotor 300 that is associatedwith the position measurement is shown (i.e., the rotor 300 is longeraxially than shown to define a shaft) for ease in illustration.

As illustrated in FIG. 4, wound coil bobbins 400 are placed around (tosurround) each stator tooth, including the middle tooth 102 and sideteeth 104 of the E-shaped cores 100 and within a frame 410. The bobbins400 include wire 402 wound around a shaft 404, thereby definingelectrical coils. Any suitable coil winding technology is used to formelectromagnetic coils 402 from wires surrounding the shafts 404 of thecoil bobbins 400. It should be noted that that size and shape of thecoil bobbins 400 can be changed, such as based on the particularapplication, size of the rotor 300, etc. For example, if the crosssection of the radial and axial teeth is a square shape (e.g., teeth 102and 104 as shown in FIG. 1), only one type of coil bobbins 400 are used.

In other configurations, for example, if the width of the radial toothmatches thickness of the axial tooth and vice versa, the same coilbobbins 400 are used and rotated 90 degrees as illustrated in FIG. 4between radial and axial teeth. In this configuration, the coil bobbins400 include two connection pins 406 on two sides of the coil bobbins 400(from which only two connection pins 406 are used and the other twoconnection pins 406 removed (e.g., cut off) depending on the orientationof the coil bobbin 400 when placed around the teeth 102 and 104 of theE-shaped cores 102). Using only one type of coil bobbins 400 reducessensor costs, but as should be appreciated, two different types of coilbobbins (e.g., bobbins having different configurations) for radial andaxial stator teeth can be used.

In operation, the electromagnetic coils 402 are supplied from a powersource 412 (e.g., a high frequency AC voltage source) that generatesfast alternating magnetic flux flowing inside the ferromagnetic parts(e.g., E-shaped cores 100) and across the air-gaps between the rotor 300and stator core 200. Magnetic flux paths are selected by setting thepolarity of the electromagnetic coils 402 in a particular way. It shouldbe noted that not all of the electromagnetic coils 402 are used as asupply coils at the same time, in some examples, if the polarity of theelectromagnetic coils 402 are configured accordingly. Additionally, byselecting the number of turns in each winding of the electromagneticcoils 402, a suitable flux density level for the magnetic circuit isset. In one configuration, magnetic flux density levels below thesaturation flux density limit of the ferromagnetic parts (stator core200 and rotor 300) are used so that the sensor operation is linearlydependent on the air-gap length between stator core 200 and rotor 300.

In some examples, the outputs of each of the windings of the coilbobbins 400 are connected to form an output bridge connection from whichradial direction x and y, as well as axial direction z, measurements areseparately made. For example, if the coordinate system x,y, and z is setas shown FIG. 2, the connections as shown in FIGS. 5 and 6 are used toobtain differential output voltages from each coordinate axis. That is,the connection arrangement 500 shown in FIG. 5 is configured to obtainx-direction and y-direction measurements, and the connection arrangement600 shown in FIG. 6 is configured to obtain z-direction measurements. Byconnecting the electromagnetic coils 402 as shown in FIGS. 5 and 6,axial coils are solely measurement coils and magnetic flux flowingtherethrough is generated with the radial coils. As such, the bridgeoutput voltage is zero if the rotor 300 is exactly in the middle of thestator cores 200 (i.e., all the radial and axial air-gaps are equal toeach other). Differential connection improves the resolution of thesensor because, for example, rotor movement in +x direction can bemeasured as positive voltage in the +x coils and negative voltage in the-x coils. Radial direction movement is compensated from the axialdirection measurement in some examples by placing four axial coils(either +coils 1, 5, 9, and 13 or minus coils 3, 7, 11, and 15 as shownin FIG. 2) to have a 90 degrees angle difference.

In some examples, the sensor air-gap is selected to be as small asmechanically possible to reduce the size of the power supply and powerconsumption of the sensor because most of the magnetic energy is storedin the air-gaps when the ferromagnetic parts are working well below thesaturation area. The air-gap in various examples is smaller than 1millimeter (mm), resulting in the accuracy requirements for thesensor-rotor air-gap to be stringent. For example, a 0.1 mm inaccuracycorrespond tens of percent inaccuracy in the air-gap, which is directlyproportional to the inductance of the electromagnetic coils 402. In oneexample, accurate machining tools are used to produce the ferromagneticE-shaped cores 100 as described herein.

In another example, a specific assembly tool inside the sensor is usedin the assembly process as described herein. After the sensor cores areassembled to form a continuous circle, the sensor cores are mountedinside a frame (e.g., the frame 410 formed from aluminum as shown inFIG. 4) so that sensor cores are not securely attached to the frame 410.In this example, the E-shaped cores 100 are mounted to the frame 410using connection screws 704 (shown in FIG. 7), which is also a costsaving method compared with gluing or shrink fitting. Using connectionscrews also increases the assembly speed compared to other conventionalmethods.

A sensor 700 is illustrated in FIG. 7, wherein a shaft 702 (e.g., aprecision machined shaft) is positioned (e.g., pushed) inside the sensor700 and powered so that the sensor 700 acts as an electromagnet pullingthe E-shaped cores 100 (formed of a ferrite material) towards the shaft702 so that air-gaps around the circular configuration are uniform andas small as possible. Thereafter, the mounting screws 704 of theE-shaped cores 100 are tightened and the assembly tool power is poweredoff and removed from the stator core 200. Then, the plastic and woundcoil bobbins 400 are attached to each stator core tooth (i.e., the teeth102 and 104) and the electromagnetic coils 402 are connected to form theconnection arrangement shown in FIGS. 5 and 6. In one example, thisconnection arrangement is performed by using a printed circuit board 800as shown in FIG. 8 to reduce the amount of space used and to provide arobust design. The printed circuit board 800 is connected to a controlcircuit 804 via electrical wires 802.

The control circuit 804 is configured to control the supply ofelectrical power to the electromagnetic coils 402, via the electricalwires 802, to drive rotation of the rotor 300 about the axis thereof.For example, when electrical power is selectively supplied to one of theelectromagnetic coils 402 (configured as stator winding) via one of theelectrical wires 802, the resulting current in the stator windinggenerates a magnetic field that couples to the rotor 300. The magneticfield associated with the magnetic material in the rotor 300 (within theE-shaped cores 100) attempts to align with the magnetic field generatedby the stator core 200, resulting in rotational movement of the rotor300. The control circuit 804 is some examples sequentially activates thestator windings so that the E-shaped cores 100 (magnet elements) of therotor 300 continuously “chase” the advancing magnetic field generated bythe stator windings.

The present disclosure provides a position sensor that can provide asignal to the control circuit 804 that is indicative of a currentposition of the rotor 300 (relative to the stator core 200) using theE-shaped cores 100. The control circuit 804 is configured to utilizethis signal when sequentially activating the stator windings to maintainproper timing of a commutation sequence.

Thus, various examples provide a sensor design that is modular. That is,designing position sensors for different sizes of rotors involves onlythe scaling of the size of the individual parts (E-cores, coil bobbins,frame and optionally the printed circuit board for connections). Thatis, an inductive position sensor is configured to measure the positionof the shaft of a magnetic bearing without the use of a cogged ring. Thepresent disclosure uses E-shaped ferrite cores and the correspondingwindings to provide the measurements. That is, the E-shaped ferritecores are arranged around the shaft as disclosed herein to form aninductive type position sensor.

FIG. 9 illustrates a flow chart of a method 900 for manufacturing asensor device, such as an inductive type position sensor for determiningthe position of the shaft within a magnetic bearing. The method 900 iseasily scalable to different sizes of shafts and magnetic bearings.

More particularly, and with reference also to FIGS. 1-8, the method 900includes at 902 arranging a plurality of E-shaped ferromagnetic cores(e.g., the E-shaped cores 100) in a offset stacked arrangement asdescribed herein. For example, the E-shaped ferromagnetic cores arearranged in a circle to define a shaft opening wherein adjacent E-shapedferromagnetic cores have one or more overlapping teeth.

The method includes coupling the E-shaped ferromagnetic cores to a frameat 904. For example, the E-shaped ferromagnetic cores are coupled withina frame (e.g., the frame 410) to define a stator core through which ashaft can be inserted. In one example, a shaft (rotor) is interestedwithin the arranged E-shaped ferromagnetic cores, which are thenenergized. The E-shaped ferromagnetic cores are then coupled to theframe in the energized state.

The method 900 further includes at 906 configuring the E-shapedferromagnetic cores to provide measurement signals used to controlrotation of the shaft. For example, in operation with the manufacturedsensor device, a control circuit (e.g., the control circuit 804)receives position signals from the E-shaped ferromagnetic cores and usesthe signals to control the energization of electromagnetic coils (e.g.,the electromagnetic coils 402) of the stator (e.g., the stator core 200formed in part by the E-shaped ferromagnetic cores) to control rotationof the shaft.

Thus, in various examples, identically shaped ferromagnetic E-shapedcores can be manufactured from laminated electrical steel sheets orsuitable ferrite material, which are both inexpensive and easy tomanufacture. The herein described design is also modular, such thatsensors for measuring different sizes of rotor can be provided byscaling the size of E-shaped cores, as well as the coil bobbins andframe part (i.e., making the E-shaped cores larger or smaller). Theposition measurement circuit in one example includes an AC voltagesource and windings of the ferromagnetic E-shaped cores wound aroundplastic coil bobbins and connected to bridge connections having outputvoltages that are linearly dependent of the rotor position in x-, y-,and z-directions. Winding connections between coil-bobbins in oneexample are implemented with printed circuit boards.

Exemplary Operating Environment

The present disclosure is operable with any electrical machine having amagnetic bearing. The control of the electrical machine is accomplishedin some examples using a computing apparatus. In one example, componentsof the computing apparatus may be implemented as a part of an electronicdevice according to one or more embodiments described in thisspecification. The computing apparatus comprises one or more processorswhich may be microprocessors, controllers or any other suitable type ofprocessors for processing computer executable instructions to controlthe operation of the electronic device. Platform software comprising anoperating system or any other suitable platform software may be providedon the apparatus to enable application software to be executed on thedevice. According to an embodiment, anomaly detection may beaccomplished by software.

Computer executable instructions may be provided using anycomputer-readable media that are accessible by the computing apparatus.Computer-readable media may include, for example, computer storage mediasuch as a memory and communications media. Computer storage media, suchas the memory, include volatile and non-volatile, removable andnon-removable media implemented in any method or technology for storageof information such as computer readable instructions, data structures,program modules or the like. Computer storage media include, but are notlimited to, RAM, ROM, EPROM, EEPROM, flash memory or other memorytechnology, CD-ROM, digital versatile disks (DVD) or other opticalstorage, magnetic cassettes, magnetic tape, magnetic disk storage orother magnetic storage devices, or any other non-transmission mediumthat can be used to store information for access by a computingapparatus. In contrast, communication media may embody computer readableinstructions, data structures, program modules, or the like in amodulated data signal, such as a carrier wave, or other transportmechanism. As defined herein, computer storage media do not includecommunication media. Therefore, a computer storage medium should not beinterpreted to be a propagating signal per se. Propagated signals per seare not examples of computer storage media. Although the computerstorage medium (the memory) is shown within the computing apparatus, itwill be appreciated by a person skilled in the art, that the storage maybe distributed or located remotely and accessed via a network or othercommunication link (e.g. using a communication interface).

The computing apparatus may comprise an input/output controllerconfigured to output information to one or more input devices and outputdevices, for example a display or a speaker, which may be separate fromor integral to the electronic device. The input/output controller mayalso be configured to receive and process an input from the one or moreinput devices, for example, a keyboard, a microphone or a touchpad.

In one embodiment, the output device may also act as the input device.An example of such a device may be a touch sensitive display. Theinput/output controller may also output data to devices other than theoutput device, e.g. a locally connected printing device. In someembodiments, a user may provide input to the input device(s) and/orreceive output from the output device(s).

The functionality described herein, such as the control functionality,can be performed, at least in part, by one or more hardware logiccomponents. According to an example, the computing apparatus isconfigured by the program code when executed by the processor(s) toexecute the embodiments of the operations and functionality described.Alternatively, or in addition, the functionality described herein can beperformed, at least in part, by one or more hardware logic components.For example, and without limitation, illustrative types of hardwarelogic components that can be used include Field-programmable Gate Arrays(FPGAs), Application-specific Integrated Circuits (ASICs),Program-specific Standard Products (ASSPs), System-on-a-chip systems(SOCs), Complex Programmable Logic Devices (CPLDs), Graphics ProcessingUnits (GPUs).

At least a portion of the functionality of the various elements in thefigures may be performed by other elements in the figures, or an entity(e.g., processor, web service, server, application program, computingdevice, etc.) not shown in the figures.

Although described in connection with an exemplary system, examples ofthe disclosure are capable of implementation with numerous othersystems, including using general purpose or special purpose computingsystem environments, configurations, or devices.

Examples of well-known computing systems, environments, and/orconfigurations that may be suitable for use with aspects of thedisclosure include, but are not limited to, mobile or portable computingdevices (e.g., smartphones), personal computers, server computers,hand-held (e.g., tablet) or laptop devices, multiprocessor systems,gaming consoles or controllers, microprocessor-based systems, set topboxes, programmable consumer electronics, mobile telephones, mobilecomputing and/or communication devices in wearable or accessory formfactors (e.g., watches, glasses, headsets, or earphones), network PCs,minicomputers, mainframe computers, distributed computing environmentsthat include any of the above systems or devices, and the like. Ingeneral, the disclosure is operable with any device with processingcapability such that it can execute instructions such as those describedherein. Such systems or devices may accept input from the user in anyway, including from input devices such as a keyboard or pointing device,via gesture input, proximity input (such as by hovering), and/or viavoice input.

Any range or device value given herein may be extended or alteredwithout losing the effect sought, as will be apparent to the skilledperson.

Although the subject matter has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described above.Rather, the specific features and acts described above are disclosed asexample forms of implementing the claims.

It will be understood that the benefits and advantages described abovemay relate to one embodiment or may relate to several embodiments. Theembodiments are not limited to those that solve any or all of the statedproblems or those that have any or all of the stated benefits andadvantages. It will further be understood that reference to ‘an’ itemrefers to one or more of those items.

The examples and embodiments illustrated and described herein as well asexamples and embodiments not specifically described herein but withinthe scope of aspects of the claims constitute exemplary means forposition sensing.

The term “comprising” is used in this specification to mean includingthe feature(s) or act(s) followed thereafter, without excluding thepresence of one or more additional features or acts.

The order of execution or performance of the operations in examples ofthe disclosure illustrated and described herein is not essential, unlessotherwise specified. That is, the operations may be performed in anyorder, unless otherwise specified, and examples of the disclosure mayinclude additional or fewer operations than those disclosed herein. Forexample, it is contemplated that executing or performing a particularoperation before, contemporaneously with, or after another operation iswithin the scope of aspects of the disclosure.

When introducing elements of aspects of the disclosure or the examplesthereof, the articles “a,” “an,” “the,” and “said” are intended to meanthat there are one or more of the elements. The terms “comprising,”“including,” and “having” are intended to be inclusive and mean thatthere may be additional elements other than the listed elements. Theterm “exemplary” is intended to mean “an example of” The phrase “one ormore of the following: A, B, and C” means “at least one of A and/or atleast one of B and/or at least one of C.”

Additional Examples

Some examples are directed to a position sensor. Such examplesspecifically include: a plurality of E-shaped ferromagnetic coresarranged to define a circular opening therethrough to receive a shaft,each E-shaped ferromagnetic core having a plurality of teeth, whereinadjacent E-shaped ferromagnetic cores of the arranged plurality ofE-shaped ferromagnetic cores have an overlapping tooth; and a framesurrounding the arranged plurality of E-shaped ferromagnetic cores, theE-shaped ferromagnetic cores coupled to the frame.

In some examples, the plurality of E-shaped ferromagnetic cores areconfigured as a stator to receive therein the shaft configured as therotor.

In some examples, each E-shaped ferromagnetic core of the plurality ofE-shaped ferromagnetic cores comprises a middle tooth and two sideteeth, one each on an opposite side of the middle tooth, the middletooth and two side teeth extending from a base to form an E-shapedprofile.

In some examples, the middle tooth had a first width and each of the twoside teeth have a second width, wherein the first width is twice thesecond width.

In some examples a side tooth of one E-shaped ferromagnetic coreentirely overlaps a side tooth of an adjacent E-shaped ferromagneticcore.

In some examples, a first set of the plurality of E-shaped ferromagneticcores are arranged in a first plane and a second set of the plurality ofE-shaped ferromagnetic cores are arranged in a second plane, the firstand second planes being parallel.

In some examples, coil bobbins have electromagnetic coils arrangedrelative to the plurality of plurality of E-shaped ferromagnetic cores,and a control circuit is coupled to the electromagnetic coils, thecontrol circuit is configured to receive position signals from theelectromagnetic coils and control power supplied to the electromagneticcoils.

In some examples, a printed circuit board forms a connection arrangementbetween the coil bobbins and the control circuit.

In some examples, outputs of each of the electromagnetic coils of thecoil bobbins are connected to form an output bridge connection, and thecontrol circuit is configured to obtain separate radial direction x andy measurements and axial direction z measurements from the output bridgeconnection.

Other examples are directed to a rotating device. Specifically, therotating device includes: a plurality of E-shaped ferromagnetic coresarranged to define a circular opening therethrough to receive a shaft,each E-shaped ferromagnetic core having a plurality of teeth including astator tooth, the plurality of E-shaped ferromagnetic cores stacked todefine offset sensing elements; a plurality of wound coil bobbins havingelectromagnetic coils and positioned around each stator tooth; a framesurrounding the arranged plurality of E-shaped ferromagnetic cores, theE-shaped ferromagnetic cores coupled to the frame; a shaft positionedwithin the circular opening of the plurality of E-shaped ferromagneticcores; a power source configured to supply power to the electromagneticcoils; and a control circuit coupled to the electromagnetic coils, thecontrol circuit configured to receive position signals from theelectromagnetic coils and control the power supplied to theelectromagnetic coils to cause rotation of the shaft.

In some examples, the plurality of E-shaped ferromagnetic cores areconfigured as a stator to receive therein the shaft configured as therotor and having a laminated steel sheet outer layer.

In some examples, each E-shaped ferromagnetic core of the plurality ofE-shaped ferromagnetic cores comprises a middle tooth and two side teethwith one of each side tooth on an opposite side of the middle tooth, themiddle tooth and two side teeth extending from a base to form anE-shaped profile.

In some examples, the middle tooth had a first width and each of the twoside teeth have a second width, wherein the first width is twice thesecond width.

In some examples, a side tooth of one E-shaped ferromagnetic coreentirely overlaps a side tooth of an adjacent E-shaped ferromagneticcore.

In some examples, a first set of the plurality of E-shaped ferromagneticcores are arranged in a first plane and a second set of the plurality ofE-shaped ferromagnetic cores are arranged in a second plane, the firstand second planes being parallel to define the offset sensing elements.

In some examples, a printed circuit board forms a connection arrangementbetween the plurality of wound coil bobbins and the control circuit.

In some examples, outputs of each of the electromagnetic coils of theplurality of wound coil bobbins are connected to form an output bridgeconnection, and the control circuit is configured to obtain separateradial direction x and y measurements and axial direction z measurementsfrom the output bridge connection.

Other examples are directed to a method for manufacturing an inductivetype position sensor. Specifically, the method includes arranging aplurality of E-shaped ferromagnetic cores in an offset stackedarrangement and defining a circular opening therethrough to receive ashaft, each E-shaped ferromagnetic core having a plurality of teeth,wherein adjacent E-shaped ferromagnetic cores of the arranged pluralityof E-shaped ferromagnetic cores have an overlapping tooth; coupling theplurality of E-shaped ferromagnetic cores to a frame; and configuringthe E-shaped ferromagnetic cores to provide measurement signals used tocontrol rotation of the shaft when inserted within the circular openingof the plurality of E-shaped ferromagnetic cores.

In some examples, the method includes configuring a control circuit toobtain separate radial direction x and y measurements and axialdirection z measurements from an output bridge connection connected towound coil bobbins positioned around the plurality of teeth.

In some examples, the method includes coupling the plurality of E-shapedferromagnetic cores to the frame in an energized state of the pluralityof E-shaped ferromagnetic cores.

Having described aspects of the disclosure in detail, it will beapparent that modifications and variations are possible withoutdeparting from the scope of aspects of the disclosure as defined in theappended claims. As various changes could be made in the aboveconstructions, products, and methods without departing from the scope ofaspects of the disclosure, it is intended that all matter contained inthe above description and shown in the accompanying drawings shall beinterpreted as illustrative and not in a limiting sense.

What is claimed is:
 1. A position sensor comprising: a plurality ofE-shaped ferromagnetic cores arranged to define a circular openingtherethrough to receive a shaft, each E-shaped ferromagnetic core havinga plurality of teeth, wherein adjacent E-shaped ferromagnetic cores ofthe arranged plurality of E-shaped ferromagnetic cores have anoverlapping tooth; and a frame surrounding the arranged plurality ofE-shaped ferromagnetic cores, the E-shaped ferromagnetic cores coupledto the frame.
 2. The position sensor of claim 1, wherein the pluralityof E-shaped ferromagnetic cores are configured as a stator to receivetherein the shaft configured as the rotor.
 3. The position sensor ofclaim 1, wherein each E-shaped ferromagnetic core of the plurality ofE-shaped ferromagnetic cores comprises a middle tooth and two sideteeth, one each on an opposite side of the middle tooth, the middletooth and two side teeth extending from a base to form an E-shapedprofile.
 4. The position sensor of claim 3, wherein the middle tooth hada first width and each of the two side teeth have a second width,wherein the first width is twice the second width.
 5. The positionsensor of claim 3, wherein a side tooth of one E-shaped ferromagneticcore entirely overlaps a side tooth of an adjacent E-shapedferromagnetic core.
 6. The position sensor of claim 1, wherein a firstset of the plurality of E-shaped ferromagnetic cores are arranged in afirst plane and a second set of the plurality of E-shaped ferromagneticcores are arranged in a second plane, the first and second planes beingparallel.
 7. The position sensor of claim 1, further comprising coilbobbins having electromagnetic coils arranged relative to the pluralityof plurality of E-shaped ferromagnetic cores, and a control circuitcoupled to the electromagnetic coils, the control circuit configured toreceive position signals from the electromagnetic coils and controlpower supplied to the electromagnetic coils.
 8. The position sensor ofclaim 7, further comprising a printed circuit board forming a connectionarrangement between the coil bobbins and the control circuit.
 9. Theposition sensor of claim 7, wherein outputs of each of theelectromagnetic coils of the coil bobbins are connected to form anoutput bridge connection, the control circuit configured to obtainseparate radial direction x and y measurements and axial direction zmeasurements from the output bridge connection.
 10. A rotating devicecomprising: a plurality of E-shaped ferromagnetic cores arranged todefine a circular opening therethrough to receive a shaft, each E-shapedferromagnetic core having a plurality of teeth including a stator tooth,the plurality of E-shaped ferromagnetic cores stacked to define offsetsensing elements; a plurality of wound coil bobbins havingelectromagnetic coils and positioned around each stator tooth; a framesurrounding the arranged plurality of E-shaped ferromagnetic cores, theE-shaped ferromagnetic cores coupled to the frame; a shaft positionedwithin the circular opening of the plurality of E-shaped ferromagneticcores; a power source configured to supply power to the electromagneticcoils; and a control circuit coupled to the electromagnetic coils, thecontrol circuit configured to receive position signals from theelectromagnetic coils and control the power supplied to theelectromagnetic coils to cause rotation of the shaft.
 11. The rotatingdevice of claim 10, wherein the plurality of E-shaped ferromagneticcores are configured as a stator to receive therein the shaft configuredas the rotor and having a laminated steel sheet outer layer.
 12. Therotating device of claim 10, wherein each E-shaped ferromagnetic core ofthe plurality of E-shaped ferromagnetic cores comprises a middle toothand two side teeth with one of each side tooth on an opposite side ofthe middle tooth, the middle tooth and two side teeth extending from abase to form an E-shaped profile.
 13. The rotating device of claim 12,wherein the middle tooth had a first width and each of the two sideteeth have a second width, wherein the first width is twice the secondwidth.
 14. The rotating device of claim 12, wherein a side tooth of oneE-shaped ferromagnetic core entirely overlaps a side tooth of anadjacent E-shaped ferromagnetic core.
 15. The rotating device of claim10, wherein a first set of the plurality of E-shaped ferromagnetic coresare arranged in a first plane and a second set of the plurality ofE-shaped ferromagnetic cores are arranged in a second plane, the firstand second planes being parallel to define the offset sensing elements.16. The rotating device of claim 10, further comprising a printedcircuit board forming a connection arrangement between the plurality ofwound coil bobbins and the control circuit.
 17. The rotating device ofclaim 16, wherein the outputs of each of the electromagnetic coils ofthe plurality of wound coil bobbins are connected to form an outputbridge connection, the control circuit configured to obtain separateradial direction x and y measurements and axial direction z measurementsfrom the output bridge connection.
 18. A method for manufacturing aninductive type position sensor, the method comprising: arranging aplurality of E-shaped ferromagnetic cores in an offset stackedarrangement and defining a circular opening therethrough to receive ashaft, each E-shaped ferromagnetic core having a plurality of teeth,wherein adjacent E-shaped ferromagnetic cores of the arranged pluralityof E-shaped ferromagnetic cores have an overlapping tooth; coupling theplurality of E-shaped ferromagnetic cores to a frame; and configuringthe E-shaped ferromagnetic cores to provide measurement signals used tocontrol rotation of the shaft when inserted within the circular openingof the plurality of E-shaped ferromagnetic cores.
 19. The method ofclaim 18, further comprising configuring a control circuit to obtainseparate radial direction x and y measurements and axial direction zmeasurements from an output bridge connection connected to wound coilbobbins positioned around the plurality of teeth.
 20. The method ofclaim 18, further comprising coupling the plurality of E-shapedferromagnetic cores to the frame in an energized state of the pluralityof E-shaped ferromagnetic cores.